Exercise to Book Chapter mapping

Exercise	Book Chapter
variables	§3.1
functions	§3.3
if	§3.5
move_semantics	§4.1
primitive_types	§4.3
structs	§5.1
enums	§6
modules	§7.2
collections	§8.1
strings	§8.2
error_handling	§9
generics	§10
option	§10.1
traits	§10.2
tests	§11.1
standard_library_types	§13.2
threads	§16.1
macros	§19.6
clippy	n/a
conversions	n/a